I. Field of the Invention
The present invention relates generally to position sensors and, more particularly, to a linear inductive position sensor.
II. Description of Related Art
Modern automotive vehicles typically include a plurality of different position sensors which generate an electric signal indicative of the position of the sensor. While some position sensors generate an electrical signal output representative of the rotational position of a sensor element, other position sensors are linear sensors which generate an electrical output signal representative of the linear position of the sensor element.
Many of the previously known sensors are formed on a printed circuit board and include an exciter or transmitter coil which is electrically excited at a high frequency AC source, such as a 2.4 megahertz AC source. A receiver coil is positioned in close proximity to the exciter coil and oftentimes within the interior of the exciter coil so that the exciter coil induces a voltage in the receiver coil.
Typically, the exciter coil is wound in a single direction and includes a plurality of loops formed on a printed circuit board while a receiver coil is formed on the printed circuit board and includes two or more oppositely wound loops. In the previously known linear inductive position sensors, a coupler element constructed of a metallic material is linearly movable relative to both the receiver coil and the exciter coil along a first direction. This coupler element interferes with the inductive coupling between the exciter coil and the receiver coil in an amount which varies linearly between the oppositely wound loops of the receiver coil as the coupler element is moved along a first direction from one end of the exciter and receiver coils and to the other end of the exciter and receiver coils. This, in turn, ideally varies the voltage output of the receiver coil linearly in synchronism with the movement of the coupler element.
The receiver coils for these previously known linear inductive position sensors have been designed so that the loops of the receiver coil have been positioned side by side to each other not only in the direction of movement of the coupler element, but also in the direction normal to the movement of the coupler element. This disadvantageously increases the overall fabrication cost of the inductive sensor and also increases the error of the output signal that may be caused by tilting of the coupler element relative to the exciter and receiver coils.